Answer to Question #214552 in Genetics for moe

Question

In butternut varieties, white fruit colour is governed by a dominant allele (W) and yellow fruit colour by the recessive (w). A dominant allele at another locus (S) produces disc shaped fruit and its recessive allele (s) yields sphere shaped fruit. If a homozygous white disc variety of genotype WWSS is crossed with a homozygous yellow sphere variety wwss, the F1 are all white disc dihybrids of genotype WwSs.

1. If the F1 is allowed to mate at random, what would be the phenotypic ratio expected in the F2 generation.
2. If a heterozygous white disc variety of genotype is crossed with a homozygous yellow sphere variety, what would be the phenotypic ratio expected in the F1 generation?

Answer 1

1.Phenotypic ratio=6:2

2.Phenotypic ratio=3:2